The virus that causes COVID-19 is spreading very easily and sustainably between people. Like the common cold, the virus is transmitted through droplets when a person coughs or sneezes. It's also possible that a person can get COVID-19 by touching a surface with the virus on it before touching their mouth, face or eyes.

The virus can live in the air for several hours, up to 24 hours on cardboard and up to two to three days on plastic and stainless steel. Cleaning surfaces with solutions containing diluted bleach should kill it.

This graphic shows the differences between symptoms of COVID-19 vs. the common cold vs. the flu.

Each infected person spreads to two or three others on average, researchers estimate. It spreads more easily than flu but less than measles, tuberculosis or some other respiratory diseases.

Patients with COVID-19 experience mild to severe respiratory illnesses. Symptoms include fever, cough and difficulty breathing and can appear two to 14 days after exposure.

Dr. Mark Loafman, chairman of Family Medicine at Cook County Health, explains the proper technique and duration for washing your hands to prevent the spread of illnesses. Scrubbing should continue for at least 20 seconds, which happens to be the amount of time it takes to hum the"Happy Birthday" song twice.

As of Friday, April 3, the CDC advised Americans to wear face coverings in public.

This recommendation was updated to respond to new research on transmission, or the spread of COVID-19. Recent studies suggest that asymptomatic individuals, or people who do not show COVID-19 symptoms but have the disease, can transmit the virus to others. This means people who feel fine can spread the coronavirus to others in close proximity by speaking, coughing and sneezing.

How many cases are confirmed globally? In the United States?

Can infected people who recover get it again?

It's not known. A few reports from China say some people had COVID-19, recovered and then fell ill again. It's unclear if that's a relapse, a new infection, or a case where the person never fully recovered in the first place.

Dr. Anthony Fauci, the nation's top infectious disease expert, told Congress on Thursday that it was unlikely that someone could get reinfected.

"We haven't formally proved it, but it is strongly likely that that's the case," he said. "Because if this acts like any other virus, once you recover, you won't get reinfected."